Foliar applications should be performed at what temperature range?

Foliar applications should be performed at what temperature range?

• A. 40 to 60 degrees F
• B. 80 to 100 degrees F
• C. 50 to 70 degrees F
• D. 60 to 80 degrees F

Answer: (D)

Foliar applications work best when temperatures are moderate, so the spray stays on the leaf long enough for the pesticide to be absorbed without stressing the plant. About 60 to 80 degrees Fahrenheit provides a balance: leaf surfaces aren’t too cold, so uptake can occur, and they aren’t too hot, which would cause rapid evaporation, poor coverage, or leaf burn. In cooler conditions (around 40–60 F), uptake slows and coverage can be uneven; in hot conditions (around 80–100 F), droplets evaporate quickly and you risk reduced effectiveness and possible phytotoxic effects. So, the 60–80 F range optimizes deposition, absorption, and plant safety.